1. Field of the Invention
The present invention is in the technical area of bicycle cranks and pedals, and pertains more specifically to a bicycle pedal and mounting assembly that provides several degrees of adjustability to both compensate for differences in hip, knee and ankle structure and function among different users of a bicycle, and to provide rehabilitation exercise for users that have chronic joint problems, particularly with the knee joint.
2. Description of Related Art
It is quite well known in the art that different persons have different anatomical features and alignment of elements of the lower body, and that a single bicycle pedal and crank arrangement will not be suitable for all such persons. Further, some people may suffer injury or at least discomfort using a crank and pedal arrangement that might be perfectly suitable for another person. One of the differences between persons that contribute to this situation are, for example, a difference in the length of legs among different people, and indeed, the fact that one person may exhibit one leg longer than the other.
Another difference is in hip structure. The human hip anatomy evolved for efficient upright walking, and typically operates such that a person's steps are substantially in-line, rather than widely separated side-to-side. This situation is important in what is known as Q-Factor in a crank assembly for a bicycle. Q-Factor is the distance horizontally across the cranks between the points where pedals may be attached. If this distance is large a user's legs will be too far separated, and unnatural forces may impinge on the ankles, knees and hips.
Yet another difference is in patella placement and action among different people. The human patella (knee cap) rides in a groove in the end of the femur, is stabilized by ligaments and tendons, and tracks in movement with the aid of certain muscles in and around the knee. The function of the patella may be affected by hip and ankle structure and operation, and in certain situations persons may suffer what is known as patella tracking disorder (PTD), and Patella Femoral Pain Syndrome (PFPS), known in one manifestation as chondromalacia patella, which may be described as softening of the anterior (back or behind) cartilage of the kneecap.
Still another difference is in ankle anatomy and function among different people. In different people the ankle may be neutral (Straight up and down), or may tend to either of pronation or supination. In pronation the foot tilts outward, the ankle inward, and in supination just the opposite. If a person's ankles pronate, that person will be uncomfortable using a crank and pedal arrangement that is more suitable for a person who's ankles supinate (and vice-versa).
And it should be considered that the anatomy and function of the hips, the knees and the ankles are all interconnected, and a problem in one region will inevitably be translated to other regions. So it should be apparent that a crank and pedal arrangement should best be designed for the anatomy and functional characteristics of each individual, although this is, in the art, a difficult and expensive proposition. Further it may be apparent that if a crank and pedal arrangement is perfectly suited to one individual, that that individual might benefit from some rather slight changes in perhaps crank length, Q-factor, and pedal angles to pronate or supinate just a bit, which might tend to help strengthen muscles and tendons, and even correct anatomy to some degree.
What is clearly needed in the art is a crank and pedal apparatus that may have several degrees of adjustability to be able to accommodate anatomical and functional differences among users, and may also serve to provide therapeutic exercise for persons suffering from conditions like PTD and PFPS, for example.